A USB is often used for data exchange between a computer and electronic products, such as a digital camera, a mobile phone, a portable hard disk, a mouse, a keyboard, a USB flash drive, and so on. It can be said that at present the USB is the most widely used peripheral bus in the computer industry and other consumer electronics industry. With flash memory capacity getting bigger and bigger, a transfer speed of the USB is upgraded as well. The USB has been upgraded to version 3.0 from 2.0 currently, and theoretically the transfer speed of the USB 3.0 is about 10 times the transfer speed of the USB2.0. Moreover, volumes of USB connectors are constantly getting smaller and smaller. In order to avoid fluid getting into an interior of the electronic products, a female mini-USB connector that is assembled on the electronic products is generally designed with a waterproof function. Generally, the female USB connector with the waterproof function includes a holding terminal seat made of plastics, a plurality of terminals disposed on the holding terminal seat, a metal case covered on the holding terminal seat, and a waterproof case made of plastics to cover around the metal case.
However, when the female USB connector is required to be disposed near an antenna in a mobile phone, as an assembling design, the metal case of the female USB connector will affect the function of the antenna in the mobile phone, even though the metal case of the female USB connector is a necessary component in order to ensure quality performance of engaging and separating the female USB connector and the male USB connector. Therefore, there is a significant need to provide an electrical connector capable of being waterproof and having a smaller metal case.